Heretofore, it has been known that high velocity low pressure (HVLP) blower systems are well suited for use in applications demanding rapid delivery of large volumes of working air such as portable paint sprayers and the like. Such HVLP systems are capable of handling the required air volume without the need to develop high pressures. Accordingly, such systems do not require large elaborate and expensive air compressor units. Typically, HVLP blower assemblies employ multistage fan units comprising various combinations of rotating and stationary fan members. The fan members are housed in an enclosure having a working air intake. The enclosure is closed by an end bracket which comprises a flat plate member having a bearing boss and an exhaust tube therein. A conventional pre-lubricated sealed or shielded ball bearing is mounted in the boss. A motor is bolted to the end bracket, the motor shaft is journaled in the bearing and is operatively connected to the rotating fan members.
Such systems are designed to develop air velocities which are highest at the exhaust. Air moving at such high velocity tends to undergo a rather dramatic increase in temperature. This increase in temperature produces several undesirable results. The heated air expands resulting in increased pressure and a great deal of turbulence at the exhaust, and as such the efficient movement of air is hindered. The high velocity air also causes the end bracket to become quite hot, the heated end bracket transfers heat to the bearing and also to the motor. Increased bearing temperature results in a change in lubricant viscosity, thereby affecting lubricant performance. Frequently, the lubricant is driven out of the bearing around the seals or shields due to the heat and pressure differential from one side of the bracket to the other.
Previously known end brackets typically have a working air exhaust comprised of a straight tubular member. Accordingly, it is necessary to provide additional means to establish a connection between the end bracket and the working air passage or hose. Typically, this is accomplished by the use of an adhesive set screw clamp or weld to mount an appropriate coupling to the exhaust tube. Accordingly, it is desired to obtain an end bracket for a HVLP blower which promotes efficient movement of expanding air, alleviates bearing and lubricant problems associated with heat, and allows for facile connection of hose fittings.